Method for producing mineral wool in pellet form



Feb. s, 1946. E, F, Quack 2,1.'- 94,1ss-

' METHOD FOR PRODUCING MINERAL WOOL 1n PELLET FORM Filed Dec. 29, 1941 2 Sheets-Sheet 1 IrhfnTBr Ida/am 7'7 152M Feb. 5, 1946. v E. F. cuslck 2,3 ,1

METHOD FOR PRODUCING MINERAL WOOL In PELLET FORM Filed 1m, 29, 1941 2*SheetS-Sheer2 V II I I! I Inflefltar 'H Ilia/am 761161 0? Patented Feb. 5, 1946 UNITED STATES PATENT FHE BIETHOD FOR PRODUCING MINERAL WOOL IN PELLET FORM Edward F. Cusick, Des Plaines, Ill.

Application December 29, 1941, Serial No. 424,804

1 Claim. This invention relates to the art of producing and treating mineral wool so that the same is delivered in pellet form without resort to the severa] steps heretofore practiced after production of the mineral wool in its substantially straight ed to carry out the method of this invention and same enters the portion of the apparatus which converts the same into pellets.

In the production of mineral wool substantially every fibre thereof has attached to it, at I one end, a grain of sand. The size and weight of these grains of sand vary appreciably and, obviously constitute the heaviest end of the fibre and must be detached. therefrom and sifted out oi or otherwise eliminated from the mass of fibre before the latter is marketable. The detachment of the sand grains has been efiected heret-ofiore during the mechanical operations whereby the fibre is converted into pellet form, this operation being followed in some instances by a sifting operation to remove the sand.

The present method of converting the mineral wool into pellets causes a loss of a very appreciable percentage of the wool due to a comminution of fibres which takes place, the comminuted fibres constituting waste which is also eliminated during the sifting operation where the latter is resorted to. If omitted, the product admixed with sandand waste is very inferior to that from which the sand and waste is eliminated.

The method now generally practiced, as aforesaid, to convert the fibres from substantially straight to pellet form, causes the pellets to be Y comparatively compact, Whereas it is desirable that they shall be lacking in compactness to. a very appreciable degree in order that a pound thereof shall occupy appreciably greater volume oi space than the pellets produced mechanically by said commonly practiced method.

Hence, a very important object of the present invention is to provide a method and apparatus 5 as aforesaid which will efiect detachment of the sand grains from the fibres and reduce the latter .to pellet form of a type appreciably lesscompact than the pellets produced by the mechanlsm now commonly used for that purpose and wherein the production of the mineral wool, its conversion into pellet form and the detachment of sand grains from the fibres constitutes a single continuous operation which is followed only by the sifting operation to eliminate the sand grains from the mass precedent to packaging the latter.

A suitable embodiment of'an apparatus adaptwhich is constructed in accordance with the in-. vention is illustrated in the accompanying drawings wherein Fig. 1 is a diagrammatic view in elevation of an apparatus, constructed in accordance with the invention, used for producing mineral wool in pellet form.

Fig. 2 is a vertical, longitudinal, sectional view illustratinga modified form of the mineral wool receiving tube'of the apparatus shown in Fig. 1.

Fig. 3 is a vertical, transverse, sectional view of the tube of Fig. 2 taken on the line 3-3 of Fig. 2.

Fig. 4 is a fragmentary bottom plan view of the tube of Fig. 2.

Fig. 1. of the drawings includes a fragmentary side elevation of a furnace, I, wherein rock is melted for discharge from the spout 2, a stream of the molten rock being indicated as flowing from said spout.

The flowing stream of molten rock passes the discharge end of a pipe 3 which is suitably connected, in a conventional manner, with a source of supply of steam under customary high pressure. The steam dischargin from said pipe impinges against the stream of molten rock and converts the latter into mineral wool in a wellknown manner.

Opposed to the discharge end of the steam ejector pipe 3, is the larger end of a truncated cone-shaped tube 5 into which the mineral wool admixed with steam is projected. The smaller end of said tube 41 is connectedby means of a pipe 5 with the suction or intake port of a blower t, the discharge port of which is connected by meansof a pipe 1 with the so-called "cyclone chamber.8 of a conventional type dust collector or an equivalent thereof as hereinafter set forth.

into a suitable receptacle such as the sifting mechanism for enacting elimination of sand.

Following the sifting operation, the wool is discharged from the last-named apparatus to suitable packaging apparatus, the latter and the said screening apparatus being omitted from illustration as constituting no part of the present invention.

The capacity of the blower 6 must be sufficient to maintain a partial vacuum at the intake end of the tube 4, so that none of the mineral wool an arcuat space is left between the outer edges of the fan blades and the surrounding wall of the blower casing of sufficient width to prevent any grinding of the mineral between said wall and the fan blade edges.

During travel of the fibres in suspension, as aforesaid, through the tube 4 and piping connecting the latter with the blower, the said particles attached to the fibres will remain disposed at the rear ends of the latter like spiders at the ends of their web-strings during migration. This may be true also after the fibres enter the blower casing wherein they are projected radially against the arcuate wall thereof and are partially collapsed or distorted by impact followed by a rolling along said wall until they are disposed into the cyclone chamber and projected against the circumferential wall of the latter where the said rolling and consequent curling operation is continued so that said fibres are delivered in a loosely curled pellet form from the discharge spout of said dust collector.

The impact aforesaid is believed to effect detachment of the sand grains from the fibres but this may occur in part during contact of the fibres with the circumferential wall of said cyclone chamber, the fibres being delivered from the dust collector free of the sand grains.

During the period of flow of fluid, as above described, the steam condenses and it is probable that the fibres then carry a film of moisture. It is quite obvious that the air admixed with the steam is saturated with moisture and it is probable that the film of moisture carried by the fibres increases their weight appreciably and may havean appreciable infiuenceon the results attained. All moisture content of the wool appears to be eliminated by the time that it is discharged from the dust collector or after it has undergone the sifting operation.

The diametric dimensions and length of the tube 4 may be varied. to meet the particular conditions of each installation, and the dust collector may be disposed otherwise than vertically.

A tube 4 which is ten to twenty feet long and about four or five feet in diameter at its intake end and two feet in diameter'at its discharge end, will be suitable for practically all installations. v i

In place of the truncated cone-shaped tube 4, other shapes of tubes may be usedas exemplified by the tubular member I3, of Fig. 2, the latter being equipped, preferably, with an arched top wall and fiat side and bottom walls, the latter being provided along its side edge portions with perforations i4 opposed to the flanges of angle bars l5 secured to the inner faces of the side walls parallel with and spaced from said bottom wall.

A conveyor belt l6 trained over pulleys l'l, suitably actuated, passes over the bottom wall of the tube IS with its side edge portions traveling in the space between the horizontal flanges of the angle bars I5 and said bottom wall and out of contact with the latter and said flanges.

Adjacent its discharge end, the rear wall portion of the tube i3 is curved upwardly and is provided with a narrow slot l8 through which said belt passes freely.

The suction created by the blower of the dust collector will cause air currents to pass through the perforations l4 and the slot l8 into the tube I3 and in part over the top surface of the belt to prevent any mineral wool settling upon said belt to become disposed in the path of the fiuid current of relatively high velocity passing through said tube l3, so that practically none of the mineral wool entering the tube can escape otherwise than through the discharge pipe it connected with the intake port of the blower.

The intake end of the tube I3 may be partly choked as shown. Obviously the belt 16 may be arranged to deliver any mineral wool remaining deposited thereupon to a suitable receptacle from which the same may be returned into the tube l3 The method of this invention will be readily understood from the foregoing, as consisting in effecting continuous rapid travel of the mineral wool from the instant of its creation and while suspended in fiuid, through a tubular structure, a blower and a cyclone chamber or the equivalents of the tube, blower and cyclone chamber, so long as said mineral wool while in suspension in said fluids is subjected to violent swirling fluid currents in a confined space as well as being projected against surfaces as aforesaid.

It is well known that the swirling of fluid created within the cyclone chamber of a dust collector will cause the solids suspended in said fluids to move gradually centripetally to the central portion of the said chamber and will be discharged therefrom partly by gravity.

It will be noted that the ducts or pipes leading to the blower 8 and from the latter to the cyclone chamber of the dust collector effect progressive changes in direction of flow of the fiuid as does also the dust collector so that the path of travel of the fiuid is substantially sinuous.

Obviously the number of changes of direction of such now of the fiuid'carrying the wool may be greatly increased in number and character so that appreciable swirling of the fluid will be.

caused during its travel to and discharge into the said cyclone chamber. Such irregulardirection of fiow of the fiuid will probably cause the mineral wool fibres to be projected repeatedly to duct surfaces during travel and efliciently etlect the ultimate result desired to be obtained,

Increase in the nor'ial or customar velocity of flow of the fluid may also be more or less advantageous if for no other purpose than to increase the rate of production of the ultimate product.

be utilized to project previously produced mineral wool into said chamber, such other means contemplating the suction flow of air into said tube responsive to operation of the blower 6, as

2,394,155 by disposing a loosemass of the wool into the path of the fluid flowing into the chamber or otherwise causing such wool to become admixed with flow of fluid such as air or steam or a mixture of both.

It will be noted that the pipe discharging intothe cyclone chamber is disposed substantially tangential to the circumferential wall of the latter in the conventional manner.

I I claim as my invention:

The method of producing mineral wool in pellet form, which consists in subjecting molten mineral to a high velocit steam-jet projected against a stream of said molten mineral in direction transverse of the direction of flow of said stream, disposing the mouth of a duct in the path of the resulting mineral wool fibres and maintaining a flow or air by suction into said mouth continuously through the said duct to a point of discharge and providing obstructions within said duct in the path of said fibres for impingement of the latter against the same to effect a gradually and progressively increasing curling of said fibres during their passage through said duct to 

